


Big Baby Brother

by Taurnil



Series: Kíli’s Special Boy [1]
Category: The Hobbit - All Media Types, The Hobbit - J. R. R. Tolkien
Genre: (Both sexual and non-sexual), Age Play, Anal Sex, Baby Fíli, Bottom Fíli, Diapers, Fluff and Smut, Infantilism, M/M, Sibling Incest, Sibling Love, Top Kíli, Urination, Wetting, nappies
Language: English
Status: Completed
Published: 2014-11-24
Updated: 2014-11-24
Packaged: 2018-02-26 19:42:11
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,386
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2664014
Author URL: https://archiveofourown.org/users/Taurnil/pseuds/Taurnil
Summary: <blockquote class="userstuff">
              <p>(Yes that title is the best I could think of.)</p><p>Fíli gets tired of being the heir and older brother sometimes. Sometimes he just needs a break...</p>
            </blockquote>





	Big Baby Brother

**Author's Note:**

  * For [GreenSorceress](https://archiveofourown.org/users/GreenSorceress/gifts), [an_odd_ducky](https://archiveofourown.org/users/an_odd_ducky/gifts).



> WARNING: This fic contains both sexual and non-sexual age play including nappies and wetting. If this makes you uncomfortable then do not read.

 

Fíli smiled to himself as he swept the floor of the forge. Just one more hour. One more hour then he would be able to go home to his little brother. Just the thought of it sent pleasant tingles up and down his entire body. Thorin could tell something was on Fíli’s mind. Not that he had any clue what it was. He knew his uncle was a smart dwarf but he did not think even the wisest could figure out what had him in such a relaxed mood. Even if Thorin as suspicious that Fili had not asked to use the privy all day.

“Are you sure you are alright Fíli?”

The golden prince jumped as his uncle asked the same question he had asked ten times that day.

“Um, yes I’m fine Thorin,” Fíli replied smiling.  Thorin looked him up and down quizzically. He knew something was different about his nephew and it positively killed him to not know what.

“You have been a little off today Fíli,” Thorin said calmly. “If you like you may head home early to try and get some rest.”

Fíli grinned, his eyes lighting up- before he remembered who was watching and tried to collect himself. But he could not stop his smile.

“Thank-you uncle,” Fíli said quickly, thrusting the broom in the lost king’s hands. “Bye!” Fíli sprinted from the forge, leaving the older dwarf bewildered and confused in his workplace.

Fíli wished he could run home but he did not want to look too foolish. He could already feel his wet nappy pressing against his groin. He was incredibly relieved that Thorin had not noticed. Kíli had never made him wear one to work before. But then again he had been a very bad boy last night. Fíli smiled cheekily to himself once more, warm fuzzy feelings spreading through his belly as the memory flooded back.

The house was empty when Fíli returned. It normally was at this time of day; Mother was still at work and Kíli was still at the academy. Fíli did not mind though, he could take a few moments alone. Fíli ran into his room and stripped himself out of his work clothes, pulling on his comfy tan undershirt that he often wore at home. Fíli crawled along the floor towards his toys wearing only the undershirt and his nappy.

Fíli loved his playtime, especially after a hard day working alongside his overbearing uncle. The eldest prince ran one of his wooden horses along the floor, while making the appropriate noises, into a troop of soldiers. Fíli was not naive, despite his troops and his nappy. He knew this was disturbing in many ways but he just could not help it! From early childhood Thorin had begun to expect so much from him. He had expected him to learn how to fight, how to work metal and all the pedantic little details about life and the world that a king needed to know. He was not allowed to go out and play with his brother and his cousins. Future kings were not allowed to get dirty or collect frog spawn or climb trees.

But Fíli could not entirely blame Thorin for his childhood. Mother had always needed his help with Kíli and keeping the house. Their father had died before Kíli was born and their mother had never fully recovered from it. When Fíli was still a baby himself he had had to take care of his baby brother. He had to change him and feed him, even though he had barely finished with these things himself. Kíli was always so much calmer when Fíli was watching over him so for the sake of his mother’s wit he had made sure to always stand guard. Fíli could not remember a time in his life when he did not have pressure or responsibility. Sometimes he just needed a rest. A break from all the orders from Thorin and all the shouting. Sometimes he could not handle being the crown prince and the older brother. Sometimes he needed to be taken care of.

Fíli sang quietly to himself, building a castle out of his wooden blocks, sitting up when he heard the front door open. He knew it would be his little brother.

“Kee!” Fíli screamed as he saw his brother come in through the bedroom door. He held out his arms, desperate to be embraced.

“Hello baby,” Kíli said, wrapping his arms around his brother. “How was work?” Fíli crinkled his long nose and turned back to his toys. Kíli moved in closer, nuzzling Fíli’s neck. “I am sorry baby,” Kíli said sweetly, pressing a kiss into his golden hair. “You don’t want to think about that right now.” Fíli turned around with a smile, giving a brother a quick kiss to show that he was not upset with him.

“Come play with me brother!” Fíli shrieked happily, pulling his brother into his pile of play things, giggling as Kíli knocked over the castle.

“In a moment darling.” Kíli smiled as he stood up, scratching Fíli beard. “Let’s get you cleaned up first, you are all grubby. Also your nappy needs changing.” Fíli pouted.

“But I want to play!”

“Now, now darling,” Kíli tutted. “Let’s not have a repeat of last night.” The younger brother reached down and patted his brother’s padded bottom, grinning as he winced. “Now then, lie down and let’s get this wet thing off you.”

Fíli obeyed, lying on the floor and waiting for Kíli patiently to return and clean him up.

“Come on sweetheart,” Kíli said, kneeling on the floor with his brother. “Open.” Fíli opened his legs on command, smiling as he heard the wet cloth squish against the floor. Before he began Kíli handed Fíli a stuffed donkey which his brother promptly took, burying his face in the warm fluff. The toy was actually Kíli’s, made for him by his Aunt when he was a baby, but he did not mind his brother borrowing it on days such as these. He closed his eyes as he felt his brother’s soft touch against his skin. His brother would change his wet nappy and would wash them for him when his mother was out of the house. All he had to do was lay back at let his brother take care of him. Kíli unpinned the cloth and pulled the material, wet with the day’s urine, out from under his brother before wiping him off with a rag.

“There we are my love, isn’t that better?” Kíli stood and folded the wet nappy before shoving it in the old pack he used for holding Fíli’s dirty baby things. He dusted his hands before holding his arms out to Fíli, beckoning him over.

“Don’t I get a clean nappy Kee?” Fíli said, looking up a Kíli with young, beautiful eyes. He looked so sweet and so innocent. Kíli wished he could just hold him forever.

“It’s time for your bath doll,” Kíli replied with a smile, rubbing his fingertips over the black grime that clung to Fíli’s skin. “Let’s get you clean again.” Fíli wrapped his arms around Kíli’s neck, clinging to him as they wondered into the washroom, moving as one.

Fíli wished that Kíli could pick him up properly, but he was much bigger than his brother was. He could yet again thank Thorin for that. But he was content with having his brother hold him close, petting his soft hair.

Kíli testing the bath water, making sure it was just the right temperature for his baby, before lowering him in. He sniffled when Kíli took away his donkey but the younger brother managed to hand him one of his wooden horses quick enough to avoid a tantrum. Kíli did not mind at all when Fíli became stroppy during his young days. It was only natural after all and he had his brother’s permission to discipline him in any way he say fit. Fíli relaxed back in the bath, letting his little brother scrub him gently but firmly, taking away all the grime, soot and oil that covered his skin. The water around them became dark and murky with the dirt. Kíli always felt sorry for Fíli. He would hate to work so hard he would end up this dirty after just one day.

“Hair time darling,” Kíli said picking up the soap. Fíli sat still and shut his eyes tight. He hated getting his hair washed! “Its ok baby I’ll be extra careful.” Kíli stayed true to his word, massaging Fíli’s scalp gently, keeping the bubbles out of his eyes. Fíli giggled playfully when his brother poured a basin of water over his head, washing away the soup. Kíli helped Fíli out of the bathtub wrapping him up in a fluffy, soft towel.

“Can we have play time now brother?” Fíli asked excitedly, reaching out for his donkey. Kíli returned the soft toy, pressing a kiss onto his brother’s nose.

“Of course we can baby,” He said with a wink. “If that’s what you want to do.” Kíli half carried Fíli back into their bedroom, lowering him down gently on the bed. “Did you enjoy your bath sweetheart?”

“Yes brother! Thank-you!” Fíli reached up towards Kíli placing a sloppy kiss on his lips.

“You are most welcome my darling,” Kíli whispered. “Most welcome.”

The two brothers kissed messily on Kíli’s bed, Fíli clinging tightly to Kíli as if he was scared he would float away. Fíli could not quite remember what came first, the inappropriate incestuous relationship or his inappropriate obsession with wanting to be treated like an infant. Either way he did not care- he cherished his brother in every way possible and loved him more than he ever thought it was possible to love another person.

“Are you still ready for your little brother baby?” Kíli asked with a wink, reaching down in-between Fíli’s legs, poking a finger inside his most private hole. “Ah yes, still stretched for me. Good boy.” Fíli flushed with pride at his brother’s praise, spreading his legs further for him. “I’ll just get some oil for my cock. I do not want my baby getting all sore.”

With Fíli still clutching at the stuffed donkey, the other hand wrapped around his brother’s neck, he watched his younger brother liberally drizzling oil over his hand before rubbing it over himself, jacking his own dick slowly, and preparing it for his brother’s body. Fíli loved Kíli’s cock; it always felt so good inside of him. His only complaint was not a wish for his brother’s cock to be bigger, but for at least to be bigger than his own. Maybe one day he would get his wish. Even so he whimpered slightly as he felt the hot flesh slowly push inside his entrance.

“Shush baby,” Kíli whispered before pressing butterfly kisses into Fíli’s still wet hair. “It’s alright. I’m here. You like brother’s cock baby?”

“Yes brother,” Fíli panted. “Thank-you for taking care of me. Thank-you for playing with me.”

“Anytime my darling.” Kíli wrapped his warm arms around Fíli’s larger body, holding him as he thrust slowly. Fíli lifted his legs, linking them around Kíli’s waist, wanting them to be as close as possible during this most intimate of acts.

Fíli felt warmth spread throughout his body, the way he always felt whenever his brother was inside of him.

“I love you so much baby,” Kíli whispered. “You’re so beautiful, my precious little boy.”

“Love…You… Too…” Fíli gasped before moaning softly through his teeth. Kíli smiled, thrusting steadily against Fíli’s sweet spot.

Fíli was never very vocal during sex, always expressing himself using the softest gasps and whimpers. Kíli loved the little whines, always trying to pull another sweet cry from his brother.

“I’ll always be here to look after you baby,” Kíli promised, kissing Fíli deeply and passionately. “You’ll never have to worry about a thing so long as brother is here to hold you and take care of you. To change you and bathe you. I’ll always love you sweetheart. I’ll always be your carer for as long as you need me.”

Fíli tried to respond but Kíli chose that moment to press hard against his sweet spot, making Fíli cling tighter to him. The younger took Fíli’s thick cock in his hand, pulling it slowly, rubbing his thumb over the sensitive head.

“Come on baby,” Kíli said, licking Fíli’s ear. “Come for me. Come for brother.”

“Thank-you Kíli,” Fíli whimpered. “Thank-you for everything. Thank-you!” Fíli bit his lip, his nails scratching down Kíli’s back as he came.

*

Fíli opened his eyes to see his brother standing beside the bed folding his clothes for tomorrow and leaving them on top of the chest of drawers they shared. When he noticed Fíli had woken he smiled at him, dropping the clothes and sitting down on the bed, brushing his hair out of his eyes.

“Hello baby, did you have a good nap?”

“Yes thank-you brother,” Fíli replied, snuggling into Kíli’s lap, encouraging his brother to pet his hair. Kíli leant down, pressing a kiss onto Fíli’s brow.

“Come on baby, it’s time to get dressed. Mama is home and she’s cooking dinner.”

Fíli nodded and went to sit up, only for Kíli to push him back down. Kíli reached under the bed and pulled out a fresh clean nappy.

“Kíli,” Fíli said nervously. “I already wore one to work around Thorin; do I have to wear one around Ma?” Kíli slapped Fíli’s thigh playfully, climbing in-between his brother’s legs.

“Now, now brother,” Kíli said with a wink. “I said you have to wear one all day. The day isn’t over yet.” Kíli slipped the nappy under his brother, getting no more protests, fastening it tight around his waist. Kíli climbed on top on Fíli’s hips, straddling him and leaning down to give Fíli a passionate kiss. “And I want that nappy to be wet by the time I put you to bed tonight.”

“Can I sleep in your bed tonight brother?” Fíli asked sweetly, wrapping his arms around Kíli, pulling him down, and snuggling up against him.

“Of course you can baby.”

The brothers allowed themselves a quiet moment, lying in the bed, holding each other tight.  

**Author's Note:**

> If you don't leave a comment I'll burn Fíli's horses! :-P


End file.
